SEDs extracted from the ATLASGAL sources’ footprints (Contreras et al. 2013, Urquhart et al. 2014, see Sect. 3.3) corresponding to the protoclusters mapped by ALMA-IMF. The actual observations are represented by black points, while the red curve depicts the PPMAP MBB that provides the best fit to the data, with the gray shaded area representing the ±2σ standard deviation of the best fit. The blue curve represents the total piecewise model described in Sect. 3.3. Downward and upward arrows respectively correspond to lower limits and saturated observations.